U.S. patent application number 17/597768 was filed with the patent office on 2022-08-18 for pyrotechnic cut-off device.
This patent application is currently assigned to ARIANEGROUP SAS. The applicant listed for this patent is ARIANEGROUP SAS. Invention is credited to Lun BREVET, Philippe LOPEZ, Romain LORENZON, Frederic MARLIN.
Application Number | 20220262587 17/597768 |
Document ID | / |
Family ID | 1000006373069 |
Filed Date | 2022-08-18 |
United States Patent
Application |
20220262587 |
Kind Code |
A1 |
MARLIN; Frederic ; et
al. |
August 18, 2022 |
PYROTECHNIC CUT-OFF DEVICE
Abstract
A pyrotechnic cut-off device includes: a pyrotechnic igniter, a
conductive portion and a movable piston, the piston being able to
be displaced in a cavity along a direction of displacement
following the actuation of the pyrotechnic igniter between a first
position of passage of the current in the conductive portion and a
second position of cut-off of the current, wherein the piston
defines a first sealing portion having a narrowing of section along
the direction of displacement, and the cavity has a wall defining a
second sealing portion which extends on either side of the
conductive portion and which has a narrowing of section along the
direction of displacement, the first sealing portion being in
contact with the second sealing portion along a contact surface
extending on either side of the conductive portion when the piston
is in the second position.
Inventors: |
MARLIN; Frederic; (LE
HAILLAN, FR) ; LORENZON; Romain; (LE HAILLAN, FR)
; BREVET; Lun; (LE HAILLAN, FR) ; LOPEZ;
Philippe; (LE HAILLAN, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ARIANEGROUP SAS |
LES MUREAUX |
|
FR |
|
|
Assignee: |
ARIANEGROUP SAS
LES MUREAUX
FR
|
Family ID: |
1000006373069 |
Appl. No.: |
17/597768 |
Filed: |
July 21, 2020 |
PCT Filed: |
July 21, 2020 |
PCT NO: |
PCT/FR2020/051315 |
371 Date: |
January 21, 2022 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01H 2039/008 20130101;
H01H 39/006 20130101 |
International
Class: |
H01H 39/00 20060101
H01H039/00; H01H 9/02 20060101 H01H009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2019 |
FR |
1908466 |
Claims
1. A pyrotechnic cut-off device comprising: a pyrotechnic igniter,
a conductive portion and a movable piston, the piston being able to
be displaced in a cavity along a direction of displacement
following the actuation of the pyrotechnic igniter between a first
position of passage of the current in the conductive portion and a
second position of cut-off of the current, characterized in that
the piston defines a first sealing portion having a narrowing of
section along the direction of displacement, and in that the cavity
has a wall defining a second sealing portion which extends on
either side of the conductive portion and which has a narrowing of
section along the direction of displacement, the first sealing
portion being in contact with the second sealing portion along a
contact surface extending on either side of the conductive portion
when the piston is in the second position, the first sealing
portion and the second sealing portion cooperating in the second
position such as to create a surface seal on either side of the
conductive portion, which makes it possible to separate in a sealed
manner the two terminals of the device between which the conductive
portion extends.
2. The device as claimed in claim 1, wherein the sections of the
piston and of the cavity are of circular or oblong shape.
3. The device as claimed in claim 1, wherein the conductive portion
is broken by impact with the piston when it passes from the first
to the second position.
4. The device as claimed in claim 3, wherein the conductive portion
has at least one fragile area to facilitate the breaking of said
conductive portion.
5. The device as claimed in claim 1, wherein the first sealing
portion has a first surface and the second sealing portion has a
second surface, said surfaces each forming an angle between
1.degree. and 10.degree. with the direction of displacement of the
piston.
6. The device as claimed in claim 1, wherein the hardness of the
material forming the first sealing portion and the hardness of the
material forming the second sealing portion are different.
7. The device as claimed in claim 1, wherein, in the first
position, the piston defines a housing and the device further
comprises a protrusion which extends from a floor of the cavity,
said protrusion being housed in the housing when the piston is in
the second position.
8. A secure electrical installation comprising a cut-off device as
claimed in claim 1, and an electrical circuit connected to the
conductive portion of said device.
9. A vehicle comprising a secure electrical installation as claimed
in claim 8.
Description
TECHNICAL FIELD
[0001] This invention relates to the general field of electrical
cut-off devices, and more particularly those of pyrotechnical
actuation type.
PRIOR ART
[0002] Pyrotechnic cut-off devices are known comprising a body in
which a pyrotechnic igniter is present, configured to, when
triggered, set in motion a piston equipped with a relief in the
direction of a bus bar to be cut. The documents WO 2016/038043 and
WO 2016/038050 show examples of devices of this type.
[0003] Known devices make it possible to obtain satisfactory
results on cut-off on low-voltage circuits. However, as soon as the
operating voltage increases, the reliability of known cut-off
devices decreases and the cut-off time increases.
[0004] There is thus still a need for a pyrotechnical cut-off
device that is more reliable at high voltages while being of a
simple and economical design.
SUMMARY OF THE INVENTION
[0005] For this purpose, the invention makes provision for a
pyrotechnic cut-off device comprising: a pyrotechnic igniter, a
conductive portion and a movable piston, the piston being able to
be displaced in a cavity along a direction of displacement
following the actuation of the pyrotechnic igniter between a first
position of passage of the current in the conductive portion and a
second position of cut-off of the current. The cut-off device is
characterized in that the piston defines a first sealing portion
having a narrowing of section along the direction of displacement,
and in that the cavity has a wall defining a second sealing portion
which extends on either side of the conductive portion and which
has a narrowing of section along the direction of displacement, the
first sealing portion being in contact with the second sealing
portion along a contact surface extending on either side of the
conductive portion when the piston is in the second position.
[0006] The first sealing portion of the piston and the second
sealing portion defined by the cavity wall can cooperate in the
second position of the piston such as to create a surface seal on
either side of the conductive portion, which makes it possible to
separate in a sealed manner the two terminals of the device between
which the conductive portion extends. Thus, the cutting of the
current and the reliability of the device are improved.
Furthermore, the narrowing of section of the sealing portions allow
the nesting of the piston in the cavity in the manner of a Morse
taper or fitting taper, which makes it possible to center the
piston in the cavity, to prevent the piston from moving once it is
in the second position and to thus ensure the maintaining of this
seal.
[0007] When the current is cut off by cutting of the conductive
portion by the piston, the device according to the invention makes
it possible to obtain a characteristic weak cutoff time,
corresponding to the time separating the moment where the
conductive portion is cut off from the moment where the current is
actually cut off, which can generally be between 50 .mu.s and 150
.mu.s.
[0008] In an exemplary embodiment, the sections of the piston and
of the cavity can be of circular or oblong shape. These shapes with
rounded sections improve the sealing between the piston and the
wall of the cavity.
[0009] In an exemplary embodiment, the conductive portion can be
broken by impact with the piston when it passes from the first to
the second position. In particular, the conductive portion can be
broken into three parts, one of which is driven by the piston.
[0010] In an exemplary embodiment, the conductive portion can have
at least one fragile area to facilitate the breaking of said
conductive portion. The fragile area can for example comprise a
plurality of tabs, or else at least one groove.
[0011] In an exemplary embodiment, the first sealing portion can
have a first surface and the second sealing portion can have a
second surface, said surfaces each forming an angle between
1.degree. and 10.degree. with the direction of displacement of the
piston. In particular, the angles made by the first surface and the
second surface can be different to allow the nesting of one sealing
portion in the other, in order to further improve the sealing.
[0012] In an exemplary embodiment, the hardness of the material
forming the first sealing portion and the hardness of the material
forming the second sealing portion can be different. The difference
in hardness between said materials may be between 50 Shore A and
100 Shore D. This feature allows the deformation of one sealing
portion with respect to the other when the piston passes into the
second position, which further improves the sealing and the cut-off
of the current.
[0013] In an exemplary embodiment, in the first position, the
piston can define a housing and the device may further comprise a
protrusion which extends from a floor of the cavity, said
protrusion being housed in the housing when the piston is in the
second position. In this configuration, the conductive portion can
be cut into three parts, one of which is driven by the piston then
folded against the protrusion in the housing when the piston is in
the second configuration. This configuration makes it possible to
improve the cut-off still further by isolating in the housing the
folded part of the conductive portion of the remaining parts
thereof.
[0014] The invention also relates to a secure electrical
installation comprising a cut-off device such as that shown above
and an electrical circuit connected to the conductive portion of
said device.
[0015] The invention finally relates to a vehicle comprising a
secure electrical installation such as that described above. Such a
vehicle may for example be an electrical motor vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a cut-off device according
to a first embodiment of the invention.
[0017] FIG. 2 is an exploded view of the device of FIG. 1.
[0018] FIG. 3 is a section and perspective view of a part of the
body of the cut-off device of FIG. 1.
[0019] FIG. 4 shows a section and perspective view of the piston of
the cut-off device of FIG. 1.
[0020] FIGS. 5A and 5B respectively show section views of the
cut-off device of FIG. 1 when the piston is in the first and in the
second position.
[0021] FIG. 6 is a section and perspective view of a part of the
body of a cut-off device according to a second embodiment of the
invention.
[0022] FIG. 7 is a section and perspective view of the piston of
the cut-off device according to the second embodiment of the
invention.
[0023] FIGS. 8A and 8B respectively show section views of the
cut-off device according to the second embodiment of the invention
when the piston is in the first and in the second position.
[0024] FIG. 9 shows a secure electrical circuit in which is present
a cut-off device according to the invention.
DESCRIPTION OF THE EMBODIMENTS
[0025] The cut-off device 100 according to a first embodiment
illustrated in FIGS. 1 to 5B comprises: a body 10 in two parts 10a
and 10b, a pyrotechnic igniter 20, a piston 30, and a conductive
portion 40.
[0026] The device 100 comprises a first 41 and a second 42
electrical terminals intended to be connected to an electrical
circuit to be cut and which here correspond to two ends of the
conductive portion 40. The conductive portion 40 here takes the
form of a bus bar or conductive tab. In a non-illustrated
embodiment, the device 100 may comprise a plurality of conductive
portions. An example of an installation comprising an electrical
circuit connected to the terminals 41 and 42 will be described in
relation to FIG. 9.
[0027] The body 10 has a generally parallelepipedal shape. The body
10 comprises a part 10a housing the different elements of the
device 100 and a cover 10b which then closes the body 10 at an
upper end. The cover 10b is attached to the part 10a by screws 10c.
The part 10a of the body 10 has an upper opening 11 into which the
piston 30 can be inserted. The cover 10b has an opening 12 to allow
connectors 21 of the pyrotechnic igniter 20 to pass. The part 10a
of the body 10 has two lateral openings 13 into which the
conductive portion 40 can be inserted.
[0028] The pyrotechnic igniter 20 comprises a pyrotechnic charge
connected to the connectors 21. The pyrotechnic charge is, when
ignited, for example, using a current traversing the connectors 21,
able to generate a pressurization gas by its combustion. The
conductive elements 21 can be connected to a control device C (FIG.
9) configured to actuate the pyrotechnic igniter 20 when an anomaly
is detected.
[0029] The piston 30 has, in this example, the shape of a
revolution solid about an axis Z. The axis Z corresponds to the
axis of displacement of the piston 30. The axis Z is transverse,
for example perpendicular, in the direction of passage of the
current in the conductive portion 40. The piston 30 comprises a
circumferential groove 31 in which a seal 32, for example an
O-ring, is intended to be housed. The piston 30 can be displaced in
a direction of displacement A along the axis Z inside the body 10
between a top position (first position) as in FIG. 5A, and a bottom
position (second position) as in FIG. 5B. The direction of
displacement A is oriented from the pyrotechnic igniter 20 toward
the conductive portion 40 or toward the second sealing portion 14b
(downward in the illustrated example). As long as the pyrotechnic
igniter 20 has not been triggered, the piston 30 is in the first
position.
[0030] The piston 30 comprises a first sealing portion 33, here
corresponding to a lower part of the piston, which has a narrowing
of section along the direction of displacement A of the piston 30.
The first sealing portion 33 here corresponds to one end of the
piston 30 facing the conductive portion 40. In this example, the
first sealing portion 33 is of frustoconical shape, for example of
circular section. The angle a1 formed by the surface of the first
sealing portion 33 with the direction of displacement of the piston
A may be between 1.degree. and 10.degree.. The angle a1 can be
measured in a plane containing the direction of displacement A (or
the axis Z). In a variant, the piston could have other sections,
for example of oblong, or else square shape. The upper part 34 of
the piston in which the groove 31 is present is meanwhile of
cylindrical shape here.
[0031] The body 10 defines a cavity 14 in which the piston 30 can
be displaced and which is traversed by the conductive portion 40.
The cavity 14 is here divided into three parts; an upper part 14a
where the wall of the cavity 14 is of generally cylindrical shape,
a second sealing portion 14b where the wall has a narrowing of
section in the direction of displacement A of the piston 30, and a
lower part 14c where the wall of the cavity is of generally
cylindrical shape. The second sealing portion 14b extends the upper
part 14a, and the lower part 14c extends the second sealing portion
14b. In this example, the second sealing portion 14b has a
frustoconical shape. In this example, the inner diameter D1 of the
cavity 14 at the level of the upper part 14a is greater than the
inner diameter D2 of the cavity at the level of the lower part 14c,
and the inner diameter of the cavity at the level of the second
sealing portion 14b gradually decreases between the upper part 14a
and the lower part 14c. The second sealing portion 14b extends on
either side of the conductive portion 40, i.e. here on either side
of the openings 13 which open into the cavity 14. The second
sealing portion 14b has a surface which forms an angle a2 with the
direction of displacement A of the piston 30 which can be between
1.degree. and 10.degree.. The angle a2 can be measured in a plane
containing the direction of displacement A (or the axis Z). The
angle a1 and the angle a2 may be identical or be slightly
different. For example, the angle a1 can be of 3.degree. and the
angle a2 can be of 4.degree., or conversely.
[0032] The section of the cavity 14 and its dimensions will be
adapted to those of the piston 30 so that the latter can be
displaced in order to cut the conductive portion 40, and the
sealing portions 33 and 14b of the piston and of the cavity wall
can cooperate in the second position, i.e. be in contact along a
contact surface extending on either side of the conductive portion
40.
[0033] The conductive portion 40 has, in this example, two fragile
areas 43 (FIG. 2) which facilitate the cut-off of the conductive
portion 40 by the piston 30. In this example, each fragile area 43
has a plurality of mutually spaced tabs 43a which connect each
terminal 41 and 42 of the conductive portion 40 to a part 44 which
is intended to be separated from the terminals 41 and 42 and driven
by the piston. Other types of fragile areas may be envisioned, for
example grooves made in the conductive portion 40. In this example,
the conductive portion 40 is cut into three parts by the piston 30.
The conductive portion 40 has a width LO. In a variant, other
cut-off configurations may be envisioned.
[0034] When the piston 30 is in the cavity 14, it separates the
cavity 14 into a first pressurization chamber 15 and a second
chamber 16 in which the conductive portion 40 is present.
[0035] In the illustrated examples, the conductive portion 40 is
separate from the body 10a. In a variant, the conductive portion 40
can be overmolded with the body 10 (here the part 10a) such as to
improve the sealing between the conductive portion 40 and the body
10.
[0036] The different operating steps of the device 100 will now be
described in relation to FIGS. 5A and 5B which show section views
thereof, respectively when the piston 30 is in the first position
and in the second position.
[0037] FIG. 5A shows the device 100 before its triggering. After
the triggering of the pyrotechnic igniter 20, the chamber 15 is
pressurized by the gas coming from the combustion of the
pyrotechnic charge, and the piston 30 is set in motion toward the
conductive portion 40 until the first sealing portion 33 of the
piston 30 then strikes the conductive portion 40. More precisely,
the first sealing portion 33 of the piston 30 then strikes the part
44 of the conductive portion 40 which then becomes detached from
the parts of the conductive portion 40 connected to the terminals
41 and 42. During the passing of the piston 30, the tabs 43a can
then fold as can be seen on the magnification of FIG. 5B to avoid
impeding the stroke of the piston 30.
[0038] When the piston 30 is in the second position or bottom
position as in FIG. 5B, its first sealing portion 33 is in surface
contact with the second sealing portion 14b of the cavity 14. In
the second position, the piston 30 is interposed between the
openings 13. In the second position, the piston 30 is interposed
between the terminals 41 and 42 of the cut-off device. In the
second position, the piston 30 is interposed between the fragments
of the broken conductive portion 40. The piston 30, in the second
position, covers the openings 13 which open into the cavity. The
contact surface between the piston 30 and the wall of the cavity 14
extends on either side of the initial location of the conductive
portion 40 (or equivalently, on either side of the openings 13)
such as to create a seal preventing the passage of the current
between the terminals 41 and 42. This contact surface can have a
frustoconical shape. In this example, the whole surface of the
second sealing portion 14b is in contact with the first sealing
portion 33. In this example, the contact surface between the piston
30 and the wall of the cavity 14 surrounds the openings 13 which
open into the cavity 14. In this way, the terminals 41 and 42 are
isolated from one another in a sealed manner. The contact surface
between the piston 30 and the wall of the cavity 14 extends around,
in particular all around (360.degree. around) the axis of
displacement Z of the piston 30. The cut part 44 of the conductive
portion 40 is meanwhile housed in the lower part 14c of the cavity
14 on a floor 14d thereof.
[0039] The materials of the first sealing portion 33 of the piston
30 and of the part of the body 10 forming the second sealing
portion 14b can be identical. As a variant, these materials may
advantageously have different hardness. The difference in hardness
between these materials may be between 50 Shore A and 100 Shore D.
Thus, the body 10 or the piston 30 may deform when the piston 30
passes from the first to the second position which provides a still
better contact between the two sealing portions, a better seal and
therefore a better cut-off of the current.
[0040] FIGS. 6 to 8B show views of a cut-off device 200 according
to a second embodiment of the invention. Unless otherwise
specified, identical reference signs between the first and second
embodiment denote identical features. With respect to the device
100, the piston 30 of the device 200 comprises a housing 35 and its
cavity 14 has a protrusion 17.
[0041] The housing 35 of the piston 30 is present in the sealing
portion 33 and opens facing the conductive portion 40 when the
piston 30 is in the first position. In this example, the housing 35
is of cylindrical shape.
[0042] The protrusion 17 extends from a floor 14d of the cavity 14.
In the first position, the protrusion 17 here extends more
precisely between the floor 14d of the cavity 14 and the conductive
portion 40. The protrusion 17 has a triangular section in a plane
containing the conductive portion 40 and the axis of displacement A
of the piston. The protrusion 17 extends along a transverse
direction T with respect to the longitudinal direction L along
which the conductive portion 40 extends.
[0043] In this example, the conductive portion 40 has grooves as
fragile areas 43, which delimit the part 44 of the conductive
portion 40 which will be separated from the terminals 41 and 42
during the cut-off.
[0044] The inner diameter D3 of the housing 35 is greater than the
width LO of the conductive portion 40 such that the housing 35 can
receive the part 44 after the cut-off.
[0045] The operation of the device 200 is similar to that of the
device 100, with the exception that, when the piston 30 is in the
second position, the part 44 of the conductive portion 40 which is
cut off and driven by the piston 30 is folded by the protrusion 17
in the housing 35. In the second position, the part 44 is located
between the protrusion 17 and the piston 30 in the housing 35,
which makes it possible to isolate the parts 44 of the terminals 41
and 42, and to further improve the current cut-off. In particular,
with this device 200, the speed of separation of the part 44 of the
terminals 41 and 42 is increased, and the distance of separation
between the part 44 and the terminals 41 and 42 is greater while
remaining of small overall dimensions.
[0046] FIG. 9 schematically shows an example of a secure electrical
installation 300 implementing a cut-off device 100 or 200 according
to the invention.
[0047] The secure electrical installation 300 comprises a secure
power supply system 310 comprising a cut-off device 100 or 200
(shown very schematically) and a power supply circuit 311. The
power supply circuit 311 here comprises an electrical generator G
connected to the second terminal 42 of the conductive portion 40 of
the cut-off device 100 or 200. The electrical generator G can for
example be a battery or an alternator.
[0048] The secure power supply system 310 further comprises a
control element C configured to actuate the pyrotechnic igniter 20
when an anomaly is detected. The control element C is connected to
the pyrotechnic igniter 20 by way of the connectors 21. The anomaly
in response to which the control element C may trigger the
pyrotechnic igniter 20 can be an electrical anomaly, such as a
crossing of a current threshold in the circuit, or a non-electrical
anomaly such as the detection of a shock, for example a sudden
deceleration of the control element, a change in temperature,
pressure etc. If an anomaly is detected, the control element C is
able to send an electrical current to the pyrotechnic igniter 20
for its triggering in order to cut the current, as previously
described.
[0049] The secure electrical installation 300 finally comprises an
electrical device D here connected to the first terminal 41 of the
conductive portion 40 of the cut-off device 100 or 200 to be
powered by the secure power supply system 310.
[0050] By way of example, a motor vehicle may comprise a secure
electrical installation 300.
* * * * *